Model Intercomparison Project
| Attribute | Value |
|---|---|
| mip_abstract | The Atlantic meridional overturning circulation (AMOC) is an important part of our climate system. The AMOC is predicted to weaken under climate change, however there are theories that it may have a tipping point beyond which recovery is difficult, hence showing quasi-irreversibility (hysteresis). Theories for why the AMOC might be a tipping point focus on the impact of freshening the North Atlantic and the role of internal feedbacks which reinforce the weakening. Although hysteresis has been seen in simple models, it has been difficult to demonstrate in comprehensive global climate models. Although it is considered unlikely that the AMOC would collapse by 2100, there is the potential that current climate models are biased to be more stable than the real world. Hence, we aim to understand the sensitivity of the AMOC to freshwater inputs (such as from glacial melt, which is not well represented in current climate models). We aim to understand the processes and feedbacks controlling the AMOC response in current generation GCMs, to understand which are the most important, and how they vary across models, and compare them with available observations. The outcome will be an improved ability to describe the circumstances under which an AMOC collapse might be triggered, with the potential to develop observable early warning signals for the approach of the AMOC towards a threshold. Project outline We propose a set of idealised experiments with CMIP6 unfluxadjusted, coupled climate models to investigate the sensitivity of the AMOC to freshwater forcing. This project is called NAHosMIP (North Atlantic Hosing Model Intercomparison Project). The aims of this project are: • Understand whether other climate models exhibit a threshold in the AMOC (whether if it is weakened sufficiently by hosing, the AMOC stays in a weak state) • Understand how different feedbacks contribute to different AMOC behaviour in different models, and what the implications of this are for the real world. • Provide sources of data that can be used in additional studies (ie impacts of AMOC weakening). NAHosMIP is not continuing for CMIP7, however some experiments are now incorporated into the CMIP7 TIPMIP project. Some data is available from https://catalogue.ceda.ac.uk/uuid/07bc349e42f94117b83e6f8289834eb7/ and https://zenodo.org/records/14884357 |
| mip_long_name | North Atlantic Hosing Model Intercomparison Project |
| mip_website | https://www.tipes.dk/na-hosing-mip/ |
| name | NAHosMIP |
| uid | 527f5c72-8c97-11ef-944e-41a8eb05f654 |